Hint

Answer

The next number is 150.
The formula is 180(n-2)/n, starting with n=3 for the first term.
180*1/3=60
180*2/4=90
180*3/5=108
180*4/6=120
...
180*10/12=150

Bonus
These numbers are the size (in degrees) of the interior angles in a regular n-sided polygon. An equilateral triangle has three 60 degree angles, a square has four 90 degree angles, a regular pentagon has five 108 degree angles, and so on. A regular dodecagon has twelve 150 degree angles.Hide